@@jasminedavies4616 I know this was a while ago but, its because you minus 4 from 1 in order to get c by itself. Effectively, you have to minus 4 from both sides of the equation to cancel out the +4 on the right side.
Stop being rude and inconsiderate of it doesn’t help you then I suggest you leave instead of leaving unnecessary rude comment thank you very much hope you do well in your exam have a nice life💞
